Depressive disorders (e.g. Major depressive disorder (MDD)) are the leading cause of disability in the United States when measured as total time lost to disability, affecting more than 18 million people annually in the USA alone. Depressive disorders, the most common of affective illnesses, include a large set of illnesses ranging from seasonal depressive disorder to chronic depression. There are currently no known available biological markers for depression; diagnosis is made by physicians or psychologists based on structured interviews with the patients. Depressive disorders are among only a few major illnesses that remain reliant upon subjective diagnoses. This contributes to under recognition, trivialization and stigmatization of these disabling illnesses.
Pre-adult onset of MDD, which occurs most often during adolescence, occurs in approximately 40% of patients with MDD. This sub-group has a poor prognosis, with high levels of adult affective disorder, substance use disorders, physical illness, and social maladjustment. This dysfunction includes problematic parenting behaviors in both women and men, with negative consequences for offspring. Thus, the public health benefit of treating adolescent MDD affects not only teens, but subsequent generations as well. In addition, the disorder is the major psychiatric risk factor for teen suicide, with rates in this group being more than 20 times greater than in the general adolescent population.
Treatments for adolescent MDD exist but response rates vary, medication side effects are unpredictable, and adolescents have lower response rates than adults. Exacerbating the problem is that 40% of youths with clinically significant levels of depression never come to the attention of a medical or mental health care provider. Many of these issues with treatment and identification are due, at least in part, to a diagnostic process that relies primarily on patient self-report. While symptom report is critical to the diagnostic process, it is subject to recall bias, the vagaries of culture-, gender-, education-influenced interpretations by the patients, and in the case of parent-report, the parent's own psychological state. Symptoms and signs, therefore, do not always discriminate between youths with and without MDD. The current diagnostic practice results in some youths who need treatment but are not getting it, and some who get treatment but may not need it. MDD treatments (e.g. antidepressants and psychotherapy) carry risks of adverse effects, and the economic cost of inappropriate treatment is high, as the effects of antidepressant medication on the developing adolescent brain are not completely understood. Conversely, the individual, societal, and economic costs of not treating a youth who truly does have MDD can also be quite high, and include suicide, hospitalization, and/or protracted impairment. The costs of misclassification for research studies are also significant in wasted dollars, time, and incorrect results.